package com.cloudinnov.utils.mongo;

import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;

import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.Assert;

public class ReflectionUtils {
	
	private static Logger logger = LoggerFactory.getLogger(ReflectionUtils.class);  
	  
    /** 
     * 调用Getter方法. 
     */  
    public static Object invokeGetterMethod(Object obj, String propertyName) {  
        String getterMethodName = "get" + StringUtils.capitalize(propertyName);  
        return invokeMethod(obj, getterMethodName, new Class[] {}, new Object[] {});  
    }  
  
    /** 
     * 调用Setter方法.使用value的Class来查找Setter方法. 
     */  
    public static void invokeSetterMethod(Object obj, String propertyName, Object value) {  
        invokeSetterMethod(obj, propertyName, value, null);  
    }  
  
    /** 
     * 调用Setter方法. 
     *  
     * @param propertyType 用于查找Setter方法,为空时使用value的Class替代. 
     */  
    public static void invokeSetterMethod(Object obj, String propertyName, Object value, Class<?> propertyType) {  
        Class<?> type = propertyType != null ? propertyType : value.getClass();  
        String setterMethodName = "set" + StringUtils.capitalize(propertyName);  
        invokeMethod(obj, setterMethodName, new Class[] { type }, new Object[] { value });  
    }  
  
    /** 
     * 直接读取对象属性值, 无视private/protected修饰符, 不经过getter函数. 
     */  
    public static Object getFieldValue(final Object obj, final String fieldName) {  
        Field field = getAccessibleField(obj, fieldName);  
  
        if (field == null) {  
            throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + obj + "]");  
        }  
  
        Object result = null;  
        try {  
            result = field.get(obj);  
        } catch (IllegalAccessException e) {  
            logger.error("不可能抛出的异常{}", e.getMessage());  
        }  
        return result;  
    }  
  
    /** 
     * 直接设置对象属性值, 无视private/protected修饰符, 不经过setter函数. 
     */  
    public static void setFieldValue(final Object obj, final String fieldName, final Object value) {  
        Field field = getAccessibleField(obj, fieldName);  
  
        if (field == null) {  
            throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + obj + "]");  
        }  
  
        try {  
            field.set(obj, value);  
        } catch (IllegalAccessException e) {  
            logger.error("不可能抛出的异常:{}", e.getMessage());  
        }  
    }  
  
    /** 
     * 循环向上转型, 获取对象的DeclaredField,   并强制设置为可访问. 
     *  
     * 如向上转型到Object仍无法找到, 返回null. 
     */  
    public static Field getAccessibleField(final Object obj, final String fieldName) {  
        Assert.notNull(obj, "object不能为空");  
        Assert.hasText(fieldName, "fieldName");  
        for (Class<?> superClass = obj.getClass(); superClass != Object.class; superClass = superClass.getSuperclass()) {  
            try {  
                Field field = superClass.getDeclaredField(fieldName);  
                field.setAccessible(true);  
                return field;  
            } catch (NoSuchFieldException e) {//NOSONAR  
                // Field不在当前类定义,继续向上转型  
            }  
        }  
        return null;  
    }  
  
    /** 
     * 直接调用对象方法, 无视private/protected修饰符. 
     * 用于一次性调用的情况. 
     */  
    public static Object invokeMethod(final Object obj, final String methodName, final Class<?>[] parameterTypes,  
            final Object[] args) {  
        Method method = getAccessibleMethod(obj, methodName, parameterTypes);  
        if (method == null) {  
            throw new IllegalArgumentException("Could not find method [" + methodName + "] on target [" + obj + "]");  
        }  
  
        try {  
            return method.invoke(obj, args);  
        } catch (Exception e) {  
            throw convertReflectionExceptionToUnchecked(e);  
        }  
    }  
  
    /** 
     * 循环向上转型, 获取对象的DeclaredMethod,并强制设置为可访问. 
     * 如向上转型到Object仍无法找到, 返回null. 
     *  
     * 用于方法需要被多次调用的情况. 先使用本函数先取得Method,然后调用Method.invoke(Object obj, Object... args) 
     */  
    public static Method getAccessibleMethod(final Object obj, final String methodName,  
            final Class<?>... parameterTypes) {  
        Assert.notNull(obj, "object不能为空");  
  
        for (Class<?> superClass = obj.getClass(); superClass != Object.class; superClass = superClass.getSuperclass()) {  
            try {  
                Method method = superClass.getDeclaredMethod(methodName, parameterTypes);  
  
                method.setAccessible(true);  
  
                return method;  
  
            } catch (NoSuchMethodException e) {//NOSONAR  
                // Method不在当前类定义,继续向上转型  
            }  
        }  
        return null;  
    }  
  
    /** 
     * 通过反射, 获得Class定义中声明的父类的泛型参数的类型. 
     * 如无法找到, 返回Object.class. 
     * eg. 
     * public UserDao extends HibernateDao<User> 
     * 
     * @param clazz The class to introspect 
     * @return the first generic declaration, or Object.class if cannot be determined 
     */  
    @SuppressWarnings({ "unchecked", "rawtypes" })  
    public static <T> Class<T> getSuperClassGenricType(final Class clazz) {  
        return getSuperClassGenricType(clazz, 0);  
    }  
  
    /** 
     * 通过反射, 获得Class定义中声明的父类的泛型参数的类型. 
     * 如无法找到, 返回Object.class. 
     *  
     * 如public UserDao extends HibernateDao<User,Long> 
     * 
     * @param clazz clazz The class to introspect 
     * @param index the Index of the generic ddeclaration,start from 0. 
     * @return the index generic declaration, or Object.class if cannot be determined 
     */  
    @SuppressWarnings("rawtypes")  
    public static Class getSuperClassGenricType(final Class clazz, final int index) {  
  
        Type genType = clazz.getGenericSuperclass();  
  
        if (!(genType instanceof ParameterizedType)) {  
            logger.warn(clazz.getSimpleName() + "'s superclass not ParameterizedType");  
            return Object.class;  
        }  
  
        Type[] params = ((ParameterizedType) genType).getActualTypeArguments();  
  
        if (index >= params.length || index < 0) {  
            logger.warn("Index: " + index + ", Size of " + clazz.getSimpleName() + "'s Parameterized Type: "  
                    + params.length);  
            return Object.class;  
        }  
        if (!(params[index] instanceof Class)) {  
            logger.warn(clazz.getSimpleName() + " not set the actual class on superclass generic parameter");  
            return Object.class;  
        }  
  
        return (Class) params[index];  
    }  
  
    /** 
     * 将反射时的checked exception转换为unchecked exception. 
     */  
    public static RuntimeException convertReflectionExceptionToUnchecked(Exception e) {  
        if (e instanceof IllegalAccessException || e instanceof IllegalArgumentException  
                || e instanceof NoSuchMethodException) {  
            return new IllegalArgumentException("Reflection Exception.", e);  
        } else if (e instanceof InvocationTargetException) {  
            return new RuntimeException("Reflection Exception.", ((InvocationTargetException) e).getTargetException());  
        } else if (e instanceof RuntimeException) {  
            return (RuntimeException) e;  
        }  
        return new RuntimeException("Unexpected Checked Exception.", e);  
    }  
}
